--fullscreen should not change the actual fullscreen option, it should be temporary

[Blackbird88]

What should happen

--fullscreen command line argument should work like it does in other emulators and only make PPSSPP fullscreen when it's used

How it works now:

1. PPSSPP is set to Windowed
2. Use --fullscreen to launch PPSSPP
3. Close it
4. Next time you launch without any arguments it's still fullscreen even though it shouldn't remember that

How it should work

1. PPSSPP is set to Windowed
2. Use --fullscreen to launch PPSSPP
3. Close it
4. Next time you launch it's Windowed, because that is the option you set

Who would this benefit

• Creates consistency in how fullscreen command line arguments work in other emulators
• Can use --fullscreen in frontend, while launching the emulator normally just for testing stuff can be Windowed

Platform (if relevant)

Windows

Games this would be useful in

PPSSPP

Other emulators or software with a similar feature

It already works like this in all other emulators I have ever used. PPSSPP is the outlier here.

Checklist

• Check the latest git build in case it's already implemented.
• Search for other requests of the same feature.